The present invention relates generally to the formation of a package on a rotatable take-up, and more particularly to a method of forming such a package and to an apparatus for carrying out the method.
It is already known in the art to form packages on rotatable take-ups by winding an elongated flexible workpiece, for example tapes, filaments, strands or the like, onto the take-up. It is also known to wind the material onto the take-up under a constant tension. The prior art experiences difficulty because as the diameter of the package increases, the tension on the workpiece tends to produce a cinching effect upon the package, that is the outer workpiece convolutions exert an inwardly directed constricted action upon the package. This, in turn, has various disadvantages. One of these is the fact that a component of the inwardly directed force tends to act axially, exerting a substantial pressure upon the end flanges of the take-up device. Moreover, and perhaps even more importantly, the inner layers of the material on the package tend to become deformed and convolutions in one layer (e.g., convolutions of a filament) tend to be pushed underneath convolutions of a subjacent layer. When such a package is subsequently unwound, this causes very substantial difficulties and frequently leads to breakage of the filament or other workpiece. Since such packages are used in extremely large numbers on automatic equipment, such as weaving machines or the like, this means downtime for the machine leading to losses in the economy of production, and also to a reduction in the quality of the goods being produced with the filament or the workpiece.
These difficulties are observed with all kinds of filaments, yarns, tapes or the like, including textile webs, and they have been observed to increase in frequency as the diameter of the package being formed increases.